Frigidaire Refrigerator

My refrig ices up in the freezer - it is a frost-free refrig. My husband defrosts with a blow dryer. When it ices up no air goes into the refrig portion. Everything has been cleaned, dusted, etc. The freezer also no longer produces ice and it has an auto icemaker. This happened at one time…no warning. Unsure as to which part to strt with first???
Thanks!:rolleyes:

This is a classic symptom of a failed defrost heater. It is also recommended, when replacing the heater, you replace the thermostat along with it. Here are your parts.

AP2114071

AP4374171